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dc.contributor.advisorNahas, Roger
dc.contributor.advisorWilliams, Douglas
dc.contributor.advisorJude, Hershel
dc.contributor.authorMarlatt, Craig W.
dc.description34 p.en_US
dc.description.abstractTwo separate samples of hop alpha acids (humulones) were purified from a CO2 extract; one of these samples was further hydrogenated to produce TH-alpha-acid (tetrahydrohumulones). Partitions of these acids underwent acyloin ring contraction isomerization reactions at 100, 90, and 80 °C under acidic (pH 5.2) and basic (pH 7.3) conditions (0.1% sample concentration) in a 3,3-dimethylglutamic acid and sodium hydroxide aqueous buffer solution. Samples were taken at fixed intervals during each reaction, quenched, and were analyzed by HPLC for amounts of starting material and product (isohumulones or tetrahydroisohumulones) present. Based on these data it was found that both alpha- and TH-alpha-acids follow first order kinetics and Arrhenius behavior in this reaction; data for isohumulone formation resemble literature values for that reaction. Additionally, TH-alpha-acids were found to have higher rate constants and lower activation energies when compared to alpha-acids isomerized under the same conditions, meaning that they react more readily under boiling-wort conditions present in beer brewing. It was also found that the ratio between the rates of formation of cis vs. trans tetrahydroisohumulone is more even in this case, another advantage that species has over its non-reduced counterpart.en_US
dc.publisherKalamazoo Collegeen_US
dc.relation.ispartofKalamazoo College Chemistry Senior Individualized Projects Collection
dc.rightsU.S. copyright laws protect this material. Commercial use or distribution of this material is not permitted without prior written permission of the copyright holder. All rights reserved.
dc.titleA Comparison of the Kinetics of Hop Alpha Acids and Their Reduced Formsen_US
KCollege.Access.ContactIf you are not a current Kalamazoo College student, faculty, or staff member, email to request access to this thesis.

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  • Chemistry Senior Individualized Projects [889]
    This collection includes Senior Individualized Projects (SIP's) completed in the Chemistry Department. Abstracts are generally available to the public, but PDF files are available only to current Kalamazoo College students, faculty, and staff.

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